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Diffstat (limited to 'lib/unicase/context.h')
-rw-r--r-- | lib/unicase/context.h | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/lib/unicase/context.h b/lib/unicase/context.h new file mode 100644 index 0000000..64d331e --- /dev/null +++ b/lib/unicase/context.h @@ -0,0 +1,65 @@ +/* Case-mapping contexts of UTF-8/UTF-16/UTF-32 substring. + Copyright (C) 2009-2018 Free Software Foundation, Inc. + Written by Bruno Haible <bruno@clisp.org>, 2009. + + This program is free software: you can redistribute it and/or modify it + under the terms of the GNU General Public License as published + by the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + + +/* The context of a prefix string combines the information of the "Before C" + conditions of the Unicode Standard, + <http://www.unicode.org/versions/Unicode5.0.0/ch03.pdf>, section 3.13, + table 3-14 "Context Specification for Casing". + + casing_prefix_context_t contains the following fields: + + // Helper for evaluating the FINAL_SIGMA condition: + // Last character that was not case-ignorable. + ucs4_t last_char_except_ignorable; + + // Helper for evaluating the AFTER_SOFT_DOTTED and AFTER_I conditions: + // Last character that was of combining class 230 ("Above") or 0. + ucs4_t last_char_normal_or_above; + + Three bits would be sufficient to carry the context information, but + that would require to invoke uc_is_cased and uc_is_property_soft_dotted + ahead of time, more often than actually needed. */ + + +/* The context of a suffix string combines the information of the "After C" + conditions of the Unicode Standard, + <http://www.unicode.org/versions/Unicode5.0.0/ch03.pdf>, section 3.13, + table 3-14 "Context Specification for Casing". + + casing_suffix_context_t contains the following fields: + + // For evaluating the FINAL_SIGMA condition: + // First character that was not case-ignorable. + ucs4_t first_char_except_ignorable; + + // For evaluating the MORE_ABOVE condition: + // Bit 0 is set if the suffix contains a character of combining class + // 230 (Above) with no character of combining class 0 or 230 (Above) + // before it. + // + // For evaluating the BEFORE_DOT condition: + // Bit 1 is set if the suffix contains a COMBINING DOT ABOVE (U+0307) + // with no character of combining class 0 or 230 (Above) before it. + // + uint32_t bits; + + Three bits would be sufficient to carry the context information, but + that would require to invoke uc_is_cased ahead of time, more often than + actually needed. */ +#define SCC_MORE_ABOVE_MASK 1 +#define SCC_BEFORE_DOT_MASK 2 |